Preparation of aldehydes from olefins



United States Patent O 3,534,103 PREPARATION OF ALDEHYDES FROM OLEFINSLawrence J. Kehoe, Ferndale, Mich., assignor to Ethyl Corporation, NewYork, N .Y., a corporation of Virginia No Drawing. Filed Mar. 30, 1967,Ser. No. 626,960 Int. Cl. C07c 45/10 U.S. Cl. 260-604 6 Claims ABSTRACTOF THE DISCLOSURE Aldehydes are prepared by reacting carbon monoxidewith an olefin and an alcohol in the presence of a ruthenium halidecatalyst. For example, when dodecene-l is reacted with methanol andcarbon monoxide in the presence of a catalytic quantity of ruthenium(IH) chloride, a product comprising O -aldehydes results. As aby-product, the alcohol corresponding to the aldehyde is also producedin many instances.

BACKGROUND OF THE INVENTION This invention relates to the preparation ofaldehydes from an olefin and an alcohol. Stated another way, thisinvention relates to a catalytic method for introducing a carbonyl groupinto a molecule.

Carbonyl insertion reactions are known. For example, Blackham US.3,119,861 teaches preparation of B-chloropropionyl chloride frompalladium (II) chloride, ethylene, and carbon monoxide. Ethylenepalladium chloride dimer is a reactive intermediate in this process.According to Alderson et al., US. 3,065,242, acid chlorides are producedby reacting olefins, hydrogen chloride, and carbon monoxide. Ascatalysts, Alderson et al. use Group VIII noble metal salts, chelatesand carbonyls. Brubaker US. 2,680,763 teaches a wide variety of reactionbetween carbon monoxide, chain transfer agents, and olefins. Ascatalysts, Brubaker employs radical forming substances, and in oneinstance, cobalt carbonyl.

SUMMARY OF THE INVENTION The heart of this invention comprises thecatalytic preparation of aldehydes from olefins, carbon monoxide, andalcohols. The reaction rate is enhanced by elevated pressures andtemperatures. The aldehyde products can be reduced to alcohols and thenused in the preparation of plasticizers or detergents.

DESCRIPTION OF PREFERRED EMBODIMENTS A most preferred embodiment isdescribed as follows: The process for the preparation of aldehydes, saidprocess comprising reacting carbon monoxide, a straight chain paraflinicu-monoolefin having 6 to 20 carbon atoms, a straight chain paraflinicmonohydric alcohol having up to 10 carbon atoms; said process beingconducted at a temperature within the range of from about 200 to about300 C. and at a pressure within the range of from about 1000 to about6000 p.-s.i.g., said process being carried out in the presence of acatalytic quantity of a simple ruthenium (HI) halide.

As mentioned immediately above, a preferred embodiment comprises use ofolefins of about six to about carbon atoms. The reason for this is thatthese olefins are comparatively inexpensive and generally readilyavailable. However, there is no known critical dependence on the size ofthe olefin; therefore, olefins having a greater or lesser number ofcarbon atoms can be used, if de- 3,534,103 Patented Oct. 13, 1970 manyinstances, the products produced therefrom are i of greater commercialvalue. The olefin need not be pure. Not only can it be admixed withother classes of substances which do not hinder the process, but olefinmixtures can be employed as starting materials.

Stable olefins are preferred in the process of this invention. An olefinis stable if the organic radicals bonded to the olefinic carbon atomsare not destroyed during the process. In other words, the preferredorganic radicals are not altered by an extraneous or competitive sidereaction and the product must be stable in the resultant reactionmixture to a significant degree. Furthermore, the organic radical orradicals attached to the doubly bonded carbon atoms must not prevent theformation of the desired product by reacting with the process reactants.Moreover, the olefin must not contain a radical which is so bulky as tounduly retard the process by steric hindrance. In other words, thedouble bond must be unhindered.

Applicable olefinic linkages are those which are not incorporated withan aromatic system. In other words, applicable double bonds are presentwithin an aliphatic or alicyclic radical. However, applicable olefinsinclude those which contain an aromatic side chain bonded to one or moreof the double bonded aliphatic or alicyclic carbon atoms.

Non-conjugated aliphatic straight-chain olefins which contain a doublebond in a terminal position are preferred examples of these preferredolefins are heptene-l, octene-l, tetradecene-l, eicosene-l, and thelike. Highly preferred olefins are the straight-chain alpha-olefinshaving '6 to 20 carbon atoms. The most preferred straightchain olefinsare hexene-l and dodecene-l.

In general, the alcohol which may be used in this process can be anyprimary or secondary alcohol having up to 18 carbon atoms. It ispreferred, however, that the alcohol be acyclic and have 12 carbon atomsor less and be free of carbon-to-carbon unsaturation. Althoughfunctional groups may be present in the alcohol molecule, as forexample, chlorine, bromine, iodine or fluorine (e.g.ethylenechlorohydrin and S-bromohexan 1 01), it is preferred that thealcohol is. free of any functional groups (other than the hydroxyradical or radicals). Thus, the most preferred alcohols are those whichhave an organic group (bonded to the hydroxy radical or radicals) solelycomposed of carbon and hydrogen.

Although carbocyclic alcohols such as cyclohexanol or phenol may beused, it is preferably to employ acyclic alcohols. Polyhydroxy radicalssuch as hexylene glycol, 1,3-butanediol, and 1,4-butanediol, may besuccessfully employed in the instant process. When using a polyhydricalcohol it is preferred that the hydroxy groups should be separated byat least one carbon atom as in a 1,3- diol, and more preferably, by atleast two carbon atoms as in a 1,4-diol. Monohydric alcohols, however,are more preferred than polyhydric alcohols.

The preferred group of alcohols which may be advantageously employed inthe process of this invention are monohydric alcohols wherein thehydroxy radical is bonded to an organic group of from 1 to about 12carbon atoms through a carbon atom of said group which is bonded to atleast one hydrogen atom, said organic group being acyclic, solelycomposed of carbon and hydrogen, and free of carbon-to-carbonunsaturation. Thus, the preferred alcohols are primary or secondaryparaffinic monohydric alcohols such as methyl alcohol, ethyl alcohol,n-propyl alcohol, isopropyl alcohol, nbutyl alcohol, isobutyl alcohol,sec-butyl alcohol, n-amyl alcohol, isoamyl alcohol, n-hexyl alcohol,n-octyl alcohol,

capryl alcohol (octanol-2), n-decyl alcohol, lauryl alcohol, myristylalcohol, cetyl alcohol, and stearyl alcohol.

The alcohol does not appear in the aldehyde or alcohol products producedby the process of this invention. Presumably the function of the alcoholis to furnish hydrogen which can be used as in thefollowing illustrativebut nonlimiting equation.

Very highly preferred alcohols of the above types are the primaryalcohols having from up to about carbon atoms, and the more preferredones are methanol, ethanol and isopropanol. Of these, the most preferredis methanol.

Simple ruthenium halides are employed as catalysts in this invention.The trivalent or tetravalent forms of these materials can be used.Preferably, a ruthenium chloride or bromide is employed, most preferablyruthenuim (III) chloride. The halide is usually charged to the reactionvessel in amounts up to percent by weight of the olefin employed.Greater or lesser amounts can be used; usually from 0.1 to 0.0001 moleof ruthenium halide are employed for each mole of olefin. Preferably,from 0.05 to 0.005 mole of halide per each mole olefin is used.

Although not bound by any theory, one molecule each of carbon monoxideand alcohol combine with each double bond reacted. Although the processof this invention can be carried out by using the reactants in thisratio, it is not necessary to do so. Other ratios frequently areemployed. For example, when the reaction is carried out in the presenceof a liquid phase, I frequently employ an excess of alcohol. The excessacts as a solvent and dispersing medium. The amount of excess is notcritical and is governed to some extent by equipment design, solubilityof the products and other reactants, and ease of separation of thedesired product. Thus, up to or 40 or more moles of alcohol per mole ofolefin can be employed, if desired.

It has been found that an excess of carbon monoxide frequently increasesthe yield. Hence, from about 1.5 to about 15 moles of carbon monoxideper mole of double bond to be reacted is usually used. Preferably, fromabout 2 to about 12 moles and most preferably from about 3 to about 10moles of carbon monoxide per mole of double bond are employed.

Thus, if the olefin is a monoolefin, from about 3 to about 10 moles ofcarbon monoxide per mole of olefin are preferably employed. Similarly,if the olefin is a diolefin, preferably from about 6 to about 20 molesof carbon monoxide per mole of olefin is used.

This process can be carried out in the presence of inert ingredients.For example, it can be carried out in the presence of a solvent and/ordispersing medium which does not enter into the reaction. Preferably,the solventdispersing medium is an inert organic liquid such as anether, hydrocarbon, or mixture thereof. Typical ethers which can beemployed are either cyclic or straight-chain ethers such astetrahydrofuran, dioxane, dimethoxyethane, diethyleneglycoldimethylether, and the like. Hydrocarbons which can be employed can beeither aliphatic or aromatic. Typical applicable hydrocarbons arecyclohexane, benzene, toluene, isooctane, No. 9 oil, kerosene, petroleumether, and the like.

The process is conducted at a reaction temperature within the range offrom about 80 to about 300 C. A preferred temperature range is fromabout 225 to about 250 C.

The process is carried out under elevated pressures.

Pressures within the range of from about 100 to about 10,000 p.s.i. areemployed. Preferred pressures are within the range of from about 2000 toabout 8000 p.s.i. Pressures Within the range of from about 2500 to about5000 p.s.i. are highly preferred.

The reaction time required by the process is not a truly independentvariable and is dependent to some extent on the nature of the olefin andthe products and upon other process variables under which the reactionis conducted. For example, when high pressures and high temperatures areused, the reaction time is usually reduced. Similarly, low temperatureand low pressures usually require a longer reaction time. In general, areaction time within the range of from about 2 to 48 hours is used.

When the reaction is carried out in the presence of a liquid phase, itis preferred to agitate the reaction mixture. Agitation is notessential, but is preferred since it affords a smooth reaction rate andtends to increase the rate of reaction. When the reaction is to becarried out as a continuous vapor-phase process, the catalyst (in a finestate of division) is frequently dispersed on an inert matrix.

The products are isolated from the reaction mixture by methods known inthe art. For example, the products can be isolated by distillation,extraction, chromatography, fractional crystallization, and othersimilar procedures.

The process of this invention is illustrated by the followingnon-limiting examples in which all parts are by weight.

EXAMPLE 1 To a suitable pressure vessel was charged 16.8 parts ofdodecene-l, 22 parts of methanol and 0.21 part of ruthenium (III)chloride. The vessel was sealed and pressured to 3000 p.s.i.g. at 18 andthen heated to 225 C. After maintaining the reaction mixture at thattemperature for 12 hours the pressure had dropped 666 p.s.i.g.

After cooling and venting the vessel, its contents, consisting of twolayers and a precipitate, were recovered. This material was treated withsuflicient acetone to result in a one-layer system and a precipitate.The precipitate was removed. Vapor phase chromatographic analysis of theliquid portion indicated that the major product was C branched aldehyde.

EXAMPLE 2 To a stainless steel pressure vessel is charged 16.8 parts ofrandom dodecene. Twenty-two parts of methanol and 0.21 part of ruthenium(III) chloride. The reaction vessel is pressured to 2800 p.s.i.g. andthen heated to 225 C. for 30 minutes and to 250 C. for 12 hours. Apressure drop occurs.

After cooling and venting, the reaction vessel is discharged, yielding areaction mixture similar to that in Example 1. A similar work-upprocedure yields a mixture of C aldehydes.

EXAMPLE 3 Following the procedure of the above examples, a C olefinfraction consisting of propylene tetramer is reacted with carbonmonoxide and ethanol at 300 C. The reaction vessel is initiallypressured with carbon monoxide so that upon reaching 300 C. the pressureis 6000 p.s.i.g. A product comprising mixed C aldehydes and alcohols isproduced. When hexene-l is the olefin employed, C aldehydes areproduced.

EXAMPLE 4 Propylene and isobutylene are copolymerized with a phosphoricacid catalyst and the resultant product fractionated to yield a cutbroiling between 76 and 99 C. This product is formylated by reaction at200 C. and an initial carbon monoxide pressure (at that temperature) of1000 p.s.i. g. The alcohol employed is ethanol; the catalyst isruthenium tetrachloride.

After 48 hours the pressure vessel is vented to atmospheric pressure anddischarged.

The product is hydrogenated using hydrogen and Raney nickel as acatalyst. There is obtained a mixture C alcohols which is useful in themanufacture of plasticizers. The alcohol product comprises 3,5-dimethylhexanol, 4,5- dimethyl hexanol, 3,4-dimethyl hexanol, 3-methyl heptanol,and 4 methyl heptanol.

Similar results are obtained when the formylation step is carried outusing ruthenium (HI) bromide when the alcohol is either n-hexanol orn-dodecanol.

Using the procedure of the above example, C alcohols are produced whenthe starting material is eicosene-l and n-decanol is used as thealcohol. When diisobutylene is formylated using the above procedure, Calcohols useful in plasticizer production are produced.

As already indicated, the product of this invention can be treated toyield alcohols which are useful as chemical intermediates. Thus, forexample, C C range products obtained by this invention can betransformed to the corresponding alcohols and these reacted withphthalic acid or phthalic anhydride to produce plasticizers. By the sametoken, the C -C alcohols produced by this invention can be sulfonated toproduce valuable detergents.

As inferred above, many of the products produced by this invention areknown compounds, and they have the many utilities known for them.

Having fully described the novel process of this invention, itsproducts, and the utility thereof, it is desired that the scope of theinvention be limited only to the lawful extent of the appended claims.

What is claimed is:

1. Process for the preparation of aldehydes, said process consistingessentially of reacting carbon monoxide, a straight chain alphamonoalkene having 6 to 20 carbon atoms, a straight chain alkanol havingup to 10 carbon atoms; said process being conducted at a temperaturewithin the range of from about 200 C. to about 300 C. and at a pressurewithin the range of from about 1000 to about 6000 p.s.i.g.; said processbeing carried out in the presence of from 0.1 to 0.0001 mole, per moleof said olefin of a catalyst selected from ruthenium (III) bromide andruthenium (III) chloride.

2. The process of claim 1 wherein said ruthenium halide is ruthenium(III) chloride.

3. The process of claim 2 wherein said olefin is dodccene-l.

4. The process of claim 1 wherein said alkanol is methanol.

5. The process of claim 2 wherein said alkanol is methanol.

6. The process of claim 3 wherein said alkanol is methanol.

References Cited UNITED STATES PATENTS 2,763,693 9/ 1956 Vander Woude etal. 260604 2,694,735 11/1954 Hull et al. 260604 2,691,046 10/1954 Hasek260604 2,876,254 3/1959 Jenner et al. 260597 3,040,090 6/ 1962 Aldersonet al. 260-483 3,020,314 2/ 1962 Alderson 260604 X FOREIGN PATENTS966,482 8/ 1964 Great Britain.

BERNARD HELFIN, Primary Examiner R. H. LILES, Assistant Examiner US. Cl.X.R. 260598; 252472

